Use of Typewriters for Multiple Copies : Offices frequently require copies of various letters and documents. The simplest method is to make the copies at the same time along with the original letter or document. Carbons, carbon-coated sheets or carbonless copy papers are often used to get a small number of legible copies. A standard typewriter can produce up to six carbon copies, whereas an electric typewriter can produce upto 20 copies as compared to four legible copies by handwriting. But where the number of copies required is more than 20, a duplicator may be used for the purpose.